thank you serum for the quik response. currently i'm pulling less than 250 watts average x .8 for 20% weight reduction = 200watts /17volt (roughly 5s under load)= 11.76 amp average. sounded safe to me, but I have no idea how high this system would spike on acceleration, or how accurate the manufactures motor #s are. I beleive an 8000kv mamba sized motor is rated for atleast 15 amps continuos, but dont know how many amps it actualy pulls in a little car. also what do you think about the driving feel of higher-voltage-low-amp vs lower-voltage-higher-amp setups with similar top speeds. My other basis for this idea is that a 70 amp controller is supposed to be good for 10th on 2s; I'm talking 5s 2.5x the voltage, so only a fraction of the amps needed. 25x2.5=62.5 amps on 2s.
I know this is cutting things close. and appriciate the negative responses also, they may save me an 80 dollar controller.